TABLE 2

Demonstration of ≥3-fold or ≥4-fold rise in specific antibody concentration between acute-a and convalescent-phaseb serum samples in nonprimary A(H1N1)pdm09 cases

IsotypeFold riseIg response (% [no. of responses/no. of paired sera]) to:
pH1 HAsH1 HA
IgM37 (2/30)3 (1/30)
IgM43 (1/30)3 (1/30)
IgG390 (27/30)43 (13/30)
IgG480 (24/30)33 (10/30)
IgA377 (23/30)17 (5/30)
IgA467 (20/30)17 (5/30)
  • a Acute-phase sera collected 1 to 7 days after symptom onset.

  • b Convalescent-phase sera collected between 15 and 52 days after symptom onset.